Typically, a machine vision system is created by a developer at the developer's location, but usually must be set-up by a customer at a later time at the customer's site. Upon moving the system to a new location for deployment, the system must be set up again, as originally configured by the developer, and typically by someone less technically sophisticated than the developer. First, the camera must be mounted, and the camera must be adjusted over five degrees of freedom (focus, aperture, (x,y,z) position of camera).
The known ways of re-establishing the set-up involve some sort of human-machine interface (HMI) that involves: getting an image on a monitor, adjusting light level by adjusting the aperture or the illumination until the image looks good, adjusting the focus by turning the focus ring on the camera until the image looks in-focus, adjusting (x,y,z) position by moving the camera so as to ensure that the image includes all objects and/or markings of interest The output of the vision system is an image of the object to be inspected, and the input might be from a mouse or a keyboard, or any other standard element of an HMI. This is by far the most common way of setting up a machine vision system.
Methods for automatically adjusting light level, focus, and (x,y,z) position are known. For example, there are methods for performing automatic gain control in cameras to obtain correct light levels. However, these known methods do not have infinite dynamic range, and so the user must manually determine the range of f-stops within which the aperture will be automatically adjusted. Also, there are auto-focus systems in many cameras. However, such auto-focus systems are not found in machine vision systems because of their high expense, and the fact that they would only be used at set-up time, but not at run time. This is because a constant camera-to-subject distance is used, and if there's not a constant camera-to-subject distance, there's typically not enough time to make focal adjustments automatically during rapidly moving industrial processes, where only a single image of an object may be captured for analysis. Further, auto-focus systems are extremely unlikely to be found in inexpensive machine vision systems, due to the high cost of auto-focus systems.
Also, X-Y-Z positioning is usually done manually by an installer or a technician.
A monitor of the typical HMI is heavy and consumes a lot of power, and is commonly the most heavy and power consuming component of a vision system. By contrast, it is possible for a computer that solely runs vision applications to operate without a monitor, and consequently it can be quite small and consume very little power, enabling it to easily obtain power solely from a 12-V battery. Yet, to provide a graphical user interface (GUI) for facilitating set-up, you need a PC or a laptop, which adds further cost, weight, and power consumption to a vision system.